Sparco 2 Liter Handheld Steel AFFF Fire Extinguisher.  If you do any sort of racing or have a nicely modified car, don't be a dumbass and invest in some fire safety.  While a handheld may not be the same as a 4 port full system install, at least its something and can give you a fighting chance in saving your car from burning down completely or you come up on an accident scene where it could save a life. 

Side note: This scenario happened to one of our employees on the Merritt Pkwy in 2019 where he came upon an accident scene with a car starting to go up in flames with driver knocked out after hitting a tree.  The 2.5# handheld bought enough time to cut the seatbelt and get the driver out. 10 seconds later the driver wouldn't have survived.